If country A uses all of its resources efficiently, it can produce a maximum of 100 units of good X. If country A uses all of its resources efficiently, it can produce a maximum of 150 units of good Y.
If country B uses all of its resources efficiently, it can produce a maximum of 75 units of good X. If country B uses all of its resources efficiently, it can produce a maximum of 125 units of good Y.
Both countries have (linear) straight line PPFs.
Which of the following must be true?